This invention relates to check valves for controlling the flow of fluids, and more particularly it relates to a check valve of a poppet type which permits a flow of fluid in one direction and closes the check valve under the influence of a back pressure.
A variety of check valves have been used in the oil industry for controlling the flow of production fluid and of various additives utilized in the field to promote the production rate.
The valves in such an environment are subject to considerable wear and exposure to abrasive, often destructive fluids which can cause damage to non-metal elements of the check valves, such as seals, conventionally made of synthetic or natural elastic materials.
In order to protect the seals and insure longer operational life of the valves, it has been suggested to limit the exposure of the seals, such as O-rings, to the harmful effects of the fluids passing through the check valve. Examples of such technical approach are disclosed in U.S. Pat. No. 2,481,482 issued on Sep. 13, 1949 to D. C. Green and U.S. Pat. No. 2,912,000 issued on Nov. 10, 1959 to D. C. Green.
It has been noted that conventional valves utilized in the field have a common problem of the O-ring's "swelling" under the influence of the destructive fluids, which leads to damage or mutilation of the O-ring and eventually results in disintegration of the O-ring piece-by-piece. The chipped away pieces then block the fluid passageway of the check valve.
It was also noted that conventional check valves sometimes last as little as a few days, depending on the composition of the fluid the flow of which the check valve controls, thereby directly affecting the cost of the operation.
The present invention, therefore, contemplates elimination of the drawbacks associated with the prior art and provision of a check valve with improved sealing capabilities.